Diagonal: a practical example
A bishop on b2 points toward c3, d4, e5, f6, g7, and h8. A pawn or piece anywhere along that path can block its influence beyond the obstruction. Moving a blocker may suddenly turn an apparently quiet bishop into a strong attacker.
How to use the idea in your games
Trace every square between an attacker and its target. A geometric line is not an immediate threat while a blocking piece remains in place.
A useful study question
Can you explain diagonal in your own words, identify it in a position, and describe when the idea does not apply? Test the explanation on a legal board before relying on it.
Connect the ideas
Bishop, Fianchetto, Discovered attack are useful next concepts. Follow the links to compare definitions and examples, then return to the complete chess glossary whenever an unfamiliar term appears.
Sources & further reading
References checked September 5, 2026. Linked services are independent of ChessRankings.com™.